1. Field of the Invention
The present invention relates generally to network devices, and more specifically to a network device and method for detecting a link failure which would cause a network to remain in a persistent state.
2. Description of the Related Art
The high speed transport capability of the IEEE 1394 serial bus network is receiving attentions to promote multimedia communications. According to the IEEE 1394 protocol, asynchronous transfer mode is used for transmission of high-reliability signals and isochronous transfer mode is supported for multimedia applications. In order to allow a wireless or optical link to be used between network devices (or nodes), the IEEE-1394 protocol specifies the use of the 8B10B coding scheme in combination with a scrambler.
If an obstacle is inadvertently placed in the path of wireless signals between sender and receiver nodes, signals transmitted from the sender node are not received by the receiver node, and hence no response returns. This results in a time-out which triggers a Bus Reset process in the sender node. Thus, the sender node restarts an initialization process to arbitrate the parent-childhood relationship with the receiver node to reconfigure the network. However, the signal transmitted during the initialization process fails to reach the receiver node. The sender node thus attempts to arbitrate with its own node, resulting in a failure to reconfigure the network. Again, the sender node restarts the initialization process. As a result, the communication between the sender node and other network nodes is also interrupted. This abnormal condition persists indefinitely. A similar problem occurs in an optical link that interconnects two network nodes.